The present invention relates to test boards used for burn-in tests of semiconductor packages such as IC and LSI, particularly to test boards with which a large number of semiconductor packages can be tested at one time to save the time and labor required for testing.
In the electronics industry, there is a trend toward miniaturization of semiconductor packages to meet the requirement of higher compactness for electronic devices. The conventional dual-in-line packages with lead pins adapted to be received in holes in a printed circuit board had a shortcoming of permitting limited miniaturization because the distance between the lead pins can be decreased only so much. Therefore, they have been replaced by new types of packages which include flat type packages with lead pins extending from four sides in a horizontal direction, small outline packages or mini-flat packages which are more compact than the flat type and have lead pins extending horizontally from two sides, and ceramic tip carrier type packages with no lead pins.
Such semiconductor packages have been heretofore tested in accordance with a sampling inspection plan using a socket such as is shown in FIG. 1. A conventional method for testing was to attach the sockets as by soldering in positions on a printed circuit board, to put the packages to be tested one by one in the sockets by hand or with a pincette, to close the lid of the sockets to provide connection between the lead pins of the package and the terminals on each socket, and to subject the packages to a burn-in test at a high temperature. After testing, the lids are opened and the tested packages are removed from the sockets one by one.
The conventional method using such a socket had the following shortcomings:
(1) Because each socket had to have a lid and a connector and therefore occupied a considerable space, only a limited number of sockets could be mounted for testing on one printed circuit board.
(2) It requires much labor and time to mount and dismount the packages by hand on and from the sockets.
(3) The spring used to press the lead pins of the package against the terminals on the socket is liable to deteriorate, causing poor connection.
(4) To meet the requirement for heat resistance, the sockets have to be made of expensive heat-resistant resin. This makes expensive the printed circuit board for testing on which the sockets are mounted.
On the other hand, users of semiconductor packages sometimes request package manufacturers to perform total or 100% inspection instead of sampling inspection to screen out all the defective parts before delivery. In order to meet this requirement, a test board is needed with which a large number of semiconductor packages can be tested at one time to save time and labor.
An object of the present invention is to provide a test board for semiconductor packages which meet the above-mentioned requirement.